Redirecting Sewer Water - Water Horror?!

[Spooder Wekd]

Hey, guys. I'm on my third playthrough of the full game, and the previous two times the only menacing thing that happened in the level where you redirect sewer water were a few monster sounds, and the muffled struggling sounds of that poor man in the chamber. This last time was different - after redirecting the water flow and on my way back to the entrance, the Shadow suddenly began growing near the exit, and I had to make a frenzied detour just to make it back through. Did I do something wrong this time, or something right?

I believe that some events in the game have to do with sanity. This one may just be random, i donno. But there are several specific points that can come out differently depending on your sanity level.Example: The painting of Daniel...